The new Miele vacuum bags have multiple layers, I would think that cutting up these bags would work well as homemade filters (but not a cheap option as the bags work out about £2 each). Nevertheless, a well fitting cotton mask (that can be washed at high temperature or soaked in bleach solution) with such a 'single use' filter, would be very useful for PWME when they really need protection if they have to go out in an exceptional circumstance.
https://www.espares.co.uk/search/ma254pt1566/vacuum-cleaners/bags/miele
My concern about adding vacuum bags etc to home made fabric masks etc, is that the vacuum bags are less porous, and so the air is less likely to travel through the area of fabric where the vacuum bag impedes the air flow.
This effectively means the air must travel elsewhere. If there is less of the fabric available for the air to flow through (cos the vacuum bag impedes flow), so a greater air movement will be forced through the gaps between face and mask.
Thus although the vacuum bag cuts down viral particles that land on it, the actual airflow to the individual’s airways is less filtered than without the vacuum bag, because of the increased pressure on the face/mask gaps.
In the same way, one could say glass is 100% effective in blocking viral particles, but adding glass (or other impermeable plastic or whatever) to a mask, would not actually increase the mask’s effectiveness. It would just reduce the surface area of the mask through which air could flow.
It might be that an extra fabric layer right under the nose/mouth area would slow air flow in the biggest use area, and so divert air to other fabric areas. Which might be good.
But I worry that the thicker the mask, the greater the pressure on the gaps.
Nice photos, @Keela Too, but it looks like there's quite a gap along the top beween the in the section between the bridge of the nose and the cheek. Or is that an optical illusion?
There is perhaps a small gap where you say, but it is not as big as there would be with the square, folded surgical masks. In truth this sort of mask is not aimed at replacing high spec masks. It can only ever be a crude barrier.
I wonder if another value of a mask is stopping yourself touching your face or at least around your mouth.
@Keela Too these masks look brilliant, is the size of your template there including seam allowance or not?
Here’s an article about mask making, here for Heathcare Providers in the US (for people with secondary roles) with a pattern and a YouTube demo: I struggle to follow patterns ....
https://www.atlantichealth.org/pati...ies-covid-19/make-facemask-help-covid-19.html